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Porsche 9A1 specs: 3.8L (231.9 ci) 6-cylinder, 102 x 77.5 mm (4.0157 x 3.0512 in) bore and stroke. Rated 385-700 hp, 2009–2019. Used in the Porsche 911. DOHC.
The Porsche MA1 (9A1) is oversquare — the 4.0157" bore exceeds the 3.0512" stroke by 31.6% — a layout that favors airflow and RPM over leverage at the crank. The 3.0512" stroke does not reach 4,000 ft/min of mean piston speed until about 7,850 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 38.7 ci (633 cc).
It is one of 3 engines in the MA1 family, all of them 231.9 ci — the differences between them are in compression, heads and rating, not displacement. 33 factory variants share these dimensions, rated from 385 to 700 hp across 2009–2019.
| Displacement | 231.9 ci / 3.8 L |
|---|---|
| Bore | 4.0157" |
| Stroke | 3.0512" |
| Cylinders | 6 |
| Bore/stroke ratio | 1.316 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 385–700 hp |
| Years | 2009–2019 |
| Bore/stroke character | 1.316 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,051 ft/min — conservative for a street engine |
| Displacement per cylinder | 38.6 ci |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2009 | 385 hp | 9A1 |
| 2010 | 385 hp | 9A1 |
| 2010 | 500 hp | 9A1 |
| 2011 | 385 hp | 9A1 |
| 2011 | 500 hp | 9A1 |
| 2011 | 530 hp | 9A1 |
| 2012 | 385 hp | 9A1 |
| 2012 | 400 hp | 9A1 |
| 2012 | 500 hp | 9A1 |
| 2012 | 530 hp | 9A1 |
| 2013 | 400 hp | 9A1 |
| 2013 | 500 hp | 9A1 |
| 2013 | 530 hp | 9A1 |
| 2014 | 400 hp | 9A1 |
| 2014 | 475 hp | 9A1 |
| 2014 | 520 hp | 9A1 |
| 2014 | 560 hp | 9A1 |
| 2015 | 400 hp | 9A1 |
| 2015 | 475 hp | 9A1 |
| 2015 | 520 hp | 9A1 |
| 2015 | 560 hp | 9A1 |
| 2016 | 400 hp | 9A1 |
| 2016 | 475 hp | 9A1 |
| 2016 | 520 hp | 9A1 |
| 2016 | 560 hp | 9A1 |
| 2017 | 540 hp | 9A1 |
| 2017 | 580 hp | 9A1 |
| 2018 | 540 hp | 9A1 |
| 2018 | 580 hp | 9A1 |
| 2018 | 700 hp | 9A1 |
| 2019 | 540 hp | 9A1 |
| 2019 | 580 hp | 9A1 |
| 2019 | 700 hp | 9A1 |